Systems and methods for determining a position for an orthodontic attachment

ABSTRACT

A method and a system for determining an orthodontic treatment plan including a tooth stripping step are provided. The method comprises: acquiring a 3D digital model of a first tooth and a second tooth of the subject, the second tooth being adjacent the first tooth; receiving a stripping request for stripping tooth material, from at least one of the first tooth along a first stripping plane and the second tooth along a second stripping plane; determining, along a surface of the first tooth, a first area of interest; determining, along the surface of the second tooth, a second area of interest; determining a distance between a first set of vertices associated with the first area of interest and a second set of vertices associated with the second area of interest; in response to the distance being greater than a predetermined distance threshold, denying, by the processor, the stripping request.

FIELD

The present technology relates generally to systems and methods fordetermining an orthodontic treatment for a subject; and in particular,to methods and systems for determining a position for an orthodonticattachment on a tooth surface.

BACKGROUND

A typical orthodontic treatment includes a number of consecutivetreatment steps in which orthodontic appliances are consecutively usedto apply forces to a subject's teeth to move the subject's teeth from arespective start position to a desired position, typically associatedwith alignment of the subject's teeth or normal occlusion thereof. Forexample, such orthodontic appliances can include brackets, braces,elastics or orthodontic aligners.

In one example, the orthodontic appliance comprises an orthodonticelastic. The orthodontic elastic can be attached to lower teeth on alower jaw and upper teeth on an upper jaw of the subject causing,through applying thereto a certain amount of elastic force, a desiredposition of the lower jaw relative to the upper jaw of the subject.

Typically, such elastics are applied to the subject's teeth via specificorthodontic attachments attached to predetermined lower and upper teethof the subject.

However, efficacy of using the orthodontic elastics depends on positionsof the orthodontic attachments on surfaces of the predetermined teeth ofthe subject. Another consideration is wear comfort to the subject,particularly when the subject must also wear an aligner in addition tothe elastic.

Certain prior art approaches have been developed to address thetechnical problem of determining an optimal position for suchorthodontic attachments.

U.S. Pat. No. 11,166,787-B1, issued on Nov. 9, 2021, assigned to ArkimosLtd., and entitled “ORTHODONTIC ATTACHMENT SYSTEMS AND METHODS”discloses systems and methods for determining a coupling point for anattachment on a tooth of a subject comprising: obtaining a digital 3Drepresentation of the tooth to which the attachment will be coupled;obtaining attachment data indicative of the attachment to be coupled tothe tooth; determining, on the digital 3D representation of the tooth, aplurality of excluded areas for the coupling point based on the digital3D representation of the tooth and the attachment data; determining thecoupling point by identifying an area on the tooth which is not in theplurality of excluded areas; and storing, in a memory of the computersystem, the determined coupling point.

U.S. Pat. No. 9,326,831-B2, issued on May 3, 2016, assigned to AlignTechnology Inc, and entitled “SYSTEM AND METHOD FOR POSITIONINGTHREE-DIMENSIONAL BRACKETS ON TEETH”, discloses systems and methods forpositioning 3D virtual brackets on teeth for the precise positioning ofconventional brackets and wire. Various reference features may becalculated for the teeth and used to calculate a position for thevirtual bracket. Reference features that are calculated include curve ofSpee, Andrew's plane, and a facial axis of the clinical crown for theteeth.

U.S. Pat. No. 9,503,282-B2, issued on Nov. 22, 2016, assigned to 3MInnovative Properties Co, and entitled “METHODS AND SYSTEMS FORDETERMINING THE POSITIONS OF ORTHODONTIC APPLIANCES”, disclosesdetermining positions of orthodontic appliances such as brackets andbuccal tubes on a patient's teeth using digital data that represents theshapes of the patient's teeth. Certain landmarks of the teeth such asthe marginal ridges are determined using software, and the softwareadjusts positions of the virtual appliances on the teeth as needed inorder to bring the marginal ridges into proper alignment at theconclusion of treatment. The resulting positions are optionally used todetermine the location of the appliances in an indirect bondingapparatus such as a transfer tray.

U.S. Pat. No. 10,136,964-B2, issued on Nov. 27, 2018, assigned to AlignTechnology Inc, and entitled “AUTOMATIC PLACEMENT OF PRECISION CUTS”,discloses an orthodontic positioning device and methods for making anorthodontic positioning device including a first patient removableorthodontic tooth positioning appliance having teeth receiving cavitiesshaped to receive and apply a resilient positioning force to a patient'steeth provided in one of an upper jaw and a lower jaw. The firstappliance includes a hook configured to receive an orthodontic elasticband. The orthodontic positioning device also includes a second patientremovable orthodontic tooth positioning appliance having teeth receivingcavities shaped to receive and apply a resilient positioning force to apatient's teeth provided in the other of the upper jaw and the lowerjaw. The second appliance includes a cutout operable to expose anorthodontic elastic band receiving member.

SUMMARY

Developers of the present technology have appreciated that a moreoptimal position for a given orthodontic attachment, such as forattaching an elastic thereto, can be determined based on referencepoints specifically determined on the surface of the given tooth.

More specifically, at least some non-limiting embodiments of the presenttechnology are directed to methods and systems for determining, on oneof a lingual surface and a buccal surface of the given tooth, a workarea based on curvature of a side surface of the given tooth. Further,the present methods and system are directed to determining, within thework area, a reference point as being a point that is most distant fromall points defining a contour of the work area. This reference point canfurther be used as a boundary within the surface of the given tooth of apositioning space for the given orthodontic attachment.

Thus, the positioning space so determined based at least on thisreference point is believed to provide a more accurate positioning ofthe given orthodontic attachment on the surface of the given tooth whichwould allow for a more accurate application of the additional forceapplied by the elastic, to the subject's teeth. In embodiments when thesubject is also wearing an aligner over the teeth, improved wear comfortcan be achieved based on the determined configuration of the positioningorthodontic attachment.

By doing so, an increased overall efficacy of the orthodontic treatmentcan be attained.

More specifically, in accordance with a first broad aspect of thepresent technology, there is provided a method of determining a positionof an orthodontic attachment on a surface of a given tooth of a subject.The method is executable by a processor. The method comprises:acquiring, by the processor, a 3D digital model of a subject's archform, the 3D digital model including a plurality of verticesrepresenting a surface of the given tooth of the subject; determining,by the processor, along the surface of the given tooth, a work area forpositioning thereon the orthodontic attachment, the work area having acontour defined by contour vertices of the plurality of vertices;determining, by the processor, a reference vertex of the work area bydetermining a vertex of the plurality of vertices within the work areawhich is most distant from all of the contour vertices, the referencevertex being representative of a boundary of a space within the workarea for positioning therein the orthodontic attachment; and storing, bythe processor, data of the reference vertex of the work area for furtheruse in determining the position of the orthodontic attachment on thesurface of the given tooth.

In some implementations of the method, the plurality of vertices of the3D digital model of the subject's arch form further includes verticesrepresenting surfaces of a plurality of subject's teeth, including thegiven tooth, and wherein: the determining the contour of the work areacomprises: obtaining, by the processor, a jaw curve extending througheach one of the plurality of subject's teeth along the subject's archform; determining, by the processor, a reference plane extending throughthe given tooth, in a buccolabial direction thereof, perpendicularly tothe jaw curve; for a given vertex representative of the surface of thegiven tooth, determining, by the processor, a respective angulardifference between a normal vector to the surface at the given vertexand the reference plane; in response to the respective angulardifference being greater than a predetermined angular threshold value,removing, by the processor, the given vertex from further consideration;and in response to the respective angular difference being lower than orequal to the predetermined angular threshold value, determining, by theprocessor, the given vertex as being representative of the work area ofthe surface of the given tooth for positioning there on the orthodonticattachment.

In some implementations of the method, the method further comprisesdetermining the jaw curve as a curve extending through respectivecenters of each one the plurality of subject's teeth.

In some implementations of the method, the determining the vertex of theplurality of vertices within the work area which is most distant fromall of the contour vertices comprises determining a vertex from which asummation of distance values to each one of the contour vertices ismaximum.

In some implementations of the method, the determining the vertex fromwhich the summation of the distance values to each one of the contourvertices is maximum comprises applying a Dijkstra algorithm.

In some implementations of the method, the method further comprisesdetermining, by the processor, the reference vertex of the work area ascorresponding to a vertical boundary of the space within the work area,towards a crown of the given tooth, for positioning thereon theorthodontic attachment.

In some implementations of the method, the method further comprises:retrieving, from a memory communicatively coupled with the processor, arespective pattern representative of a shape of the space within thework area associated with the given tooth for positioning thereon theorthodontic attachment; fitting the respective pattern within the workarea such that at least one first peak point of the respective patternpositioned towards the crown of the given tooth matches the referencevertex of the work area; and adding, by the processor, to the 3D digitalmodel of the subject's arch form, an indication of the respectivepattern fitted within the work area associated with the given tooth forfurther use in producing the orthodontic appliance.

In some implementations of the method, the plurality of vertices of the3D digital model further includes vertices representing a gingiva of thesubject, and the method further comprises: obtaining, by the processor,a segmentation contour representative of a boundary between the giventooth and the gingiva; identifying, on the segmentation contour alongthe work area, based on a predetermined rule, additional referencevertices for positioning the orthodontic attachment; and wherein: thefitting further comprises fitting the respective pattern within the workarea such that at least one second peak point of the respective pattern,oppositely facing the at least one first peak point, matches arespective one of the additional reference vertices.

In some implementations of the method, the additional reference verticesare distributed uniformly along the segmentation contour.

In some implementations of the method, the method further comprisesdetermining the segmentation contour.

In some implementations of the method, the fitting comprises scaling therespective pattern within the work area in at least one directionthereof.

In some implementations of the method, the orthodontic attachment is tobe applied to the given tooth concurrently with an orthodonticappliance; and a contour of the space within the work area associatedwith the given tooth defines a cut-out in the orthodontic appliance foraccommodating therein the orthodontic attachment when applied to thesubject's arch form.

In some implementations of the method, the method further comprisesdetermining, based at least on a configuration of the cut-out, a profileof a free end of the orthodontic appliance configured for accommodatingtherein the orthodontic attachment.

In some implementations of the method, the method further comprisescausing manufacture of the orthodontic appliance based at least on thedetermined profile of the free end thereof.

In some implementations of the method, the orthodontic attachment is anelastic retaining member.

In some implementations of the method, the orthodontic appliance is anorthodontic aligner.

In accordance with a second broad aspect of the present technology,there is provided a system for determining a position of an orthodonticattachment on a surface of a given tooth of a subject. The systemcomprises: a processor and a non-transitory computer-readable memorystoring instructions. The processor, upon executing the instructions, isconfigured to: acquire a 3D digital model of a subject's arch form, the3D digital model including a plurality of vertices representing asurface, at least, of the given tooth of the subject; determine, alongthe surface of the given tooth, a work area for positioning thereon theorthodontic attachment, the work area having a contour defined bycontour vertices of the plurality of vertices, the reference vertexbeing representative of a boundary of a space within the work area forpositioning therein the orthodontic attachment; and determine areference vertex of the work area by determining a vertex of theplurality of vertices within the work area which is most distant fromall of the contour vertices; and store data of the reference vertex ofthe work area for further use in positioning the orthodontic attachmenton the surface of the given tooth.

In some implementations of the system, the plurality of vertices of the3D digital model of the subject's arch form further includes verticesrepresenting surfaces of a plurality of subject's teeth, including thegiven tooth, and wherein to determine the contour of the work area, theprocessor is further configured to: obtain a jaw curve extending througheach one of the plurality of subject's teeth along the subject's archform; determine a reference plane extending through the given tooth, ina buccolabial direction thereof, perpendicularly to the jaw curve; for agiven vertex representative of the surface of the given tooth, determinea respective angular difference between a normal vector to the surfaceat the given vertex and the reference plane; in response to therespective angular difference being greater than a predetermined angularthreshold value, remove the given vertex from further consideration; andin response to the respective angular difference being lower than orequal to the predetermined angular threshold value, determine the givenvertex as being representative of the work area of the surface of thegiven tooth for positioning there on the orthodontic attachment.

In some implementations of the system, to determine the vertex of theplurality of vertices within the work area which is most distant fromall of the contour vertices, the processor is configured to determine avertex from which a summation of distance values to each one of thecontour vertices is maximum.

In some implementations of the system, the processor is furtherconfigured to: determine the reference vertex of the work area ascorresponding to a vertical boundary of a space within the work area,towards a crown of the given tooth, for positioning thereon theorthodontic attachment; retrieve, from the non-transitorycomputer-readable memory, a respective pattern representative of a shapeof the space within the work area associated with the given tooth forpositioning thereon the orthodontic attachment; fir the respectivepattern within the work area such that at least one first peak point ofthe respective pattern positioned towards the crown of the given toothmatches the reference vertex of the work area; and add, to the 3Ddigital model of the subject's arch form, an indication of therespective pattern fitted within the work area associated with the giventooth for further use in producing the orthodontic appliance.

In the context of the present specification, unless expressly providedotherwise, the term “orthodontic treatment” is broadly referred to asany type of medical intervention aimed at correcting malocclusionsassociated with the teeth or jaw of the subject, or moving the subject'steeth or jaws for any reason, including surgical and non-surgicalmanipulations, such as, but not limited to, using one or more ofaligners, brackets, multi-strand wires, strips, retainers, and plates.Further, the orthodontic treatment, as referred to herein, may bedetermined automatically by a software, based on image data and otherinputs associated with the subject, or semi-automatically with inputfrom a practitioner in the field of dentistry (such as an orthodontist,a maxillofacial surgeon, for example).

In the context of the present specification, unless expressly providedotherwise, a computer system may refer, but is not limited to, an“electronic device”, an “operation system”, a “system”, a“computer-based system”, a “controller unit”, a “control device” and/orany combination thereof appropriate to the relevant task at hand.

In the context of the present specification, unless expressly providedotherwise, the expression “computer-readable medium” and “memory” areintended to include media of any nature and kind whatsoever,non-limiting examples of which include RAM, ROM, disks (CD-ROMs, DVDs,floppy disks, hard disk drives, etc.), USB keys, flash memory cards,solid-state-drives, and tape drives.

In the context of the present specification, a “database” is anystructured collection of data, irrespective of its particular structure,the database management software, or the computer hardware on which thedata is stored, implemented or otherwise rendered available for use. Adatabase may reside on the same hardware as the process that stores ormakes use of the information stored in the database or it may reside onseparate hardware, such as a dedicated server or plurality of servers.

In the context of the present specification, unless expressly providedotherwise, the words “first”, “second”, “third”, etc. have been used asadjectives only for the purpose of allowing for distinction between thenouns that they modify from one another, and not for the purpose ofdescribing any particular relationship between those nouns.

Embodiments of the present technology each have at least one of theabove-mentioned objects and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presenttechnology that have resulted from attempting to attain theabove-mentioned object may not satisfy this object and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects and advantages ofembodiments of the present technology will become apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present technology, as well as otheraspects and further features thereof, reference is made to the followingdescription which is to be used in conjunction with the accompanyingdrawings, where:

FIG. 1 depicts a perspective view of lower and upper arch forms of asubject depicting examples of malocclusions of some of subject's teeth,in accordance with certain non-limiting embodiments of the presenttechnology;

FIGS. 2A and 2B depict a side view and a cross-sectional view throughline 3-3, respectively, of an orthodontic appliance applied to thesubject's teeth that may be configured to treat the malocclusions of thesubject's teeth present in FIG. 1 , in accordance with certainnon-limiting embodiments of the present technology;

FIG. 3A depicts a schematic diagram of an auxiliary orthodonticappliance applied to the subject's teeth concurrently with theorthodontic appliance of FIGS. 2A and 2B, in accordance with certainembodiments of the present technology;

FIG. 3B depicts a schematic diagram of an orthodontic attachment usedfor retaining the auxiliary orthodontic appliance of FIG. 3A on thesubject's teeth, in accordance with certain non-limiting embodiments ofthe present technology;

FIG. 4 depicts a schematic diagram of a computer system for determininga position of the orthodontic attachment of FIG. 3A on a surface of agiven tooth of a subject, in accordance with certain non-limitingembodiments of the present technology;

FIG. 5 depicts a schematic diagram of a computing environment, includinga processor, of the system of FIG. 4 , in accordance with certainembodiments of the present technology;

FIG. 6 depicts a 3D digital model of the lower arch form of the subjectpresent in FIG. 1 used, by the processor of FIG. 5 , to determine theposition for the orthodontic attachment of FIG. 3A, in accordance withcertain non-limiting embodiments of the present technology;

FIG. 7 depicts a 3D digital model of the given tooth of the subjectisolated, by the processor of FIG. 5 , from the 3D digital model of FIG.6 , in accordance with certain non-limiting embodiments of the presenttechnology;

FIG. 8 depicts a schematic diagram of a top view of the 3D digital modelof the lower arch form of FIG. 6 illustrating an approach to determininga jaw curve extending through the subject's teeth, in accordance withcertain non-limiting embodiments of the present technology;

FIG. 9A depicts a schematic diagram of a top view of the 3D digitalmodel of the given tooth illustrating an approach for determining, bythe processor of FIG. 5 , a work area on a surface of the given toothfor positioning thereon the orthodontic attachment of FIG. 3B, inaccordance with certain non-limiting embodiments of the presenttechnology;

FIG. 9B depicts a schematic diagram of a step for determining, by theprocessor of FIG. 5 , a reference vertex within the work area of FIG. 9Arepresentative of a first vertical boundary for a positioning space forthe orthodontic attachment of FIG. 3B on the surface of the given tooth,in accordance with certain non-limiting embodiments of the presenttechnology;

FIGS. 10A and 10B depict a top view of a tooth-gingiva segmentation loopbetween the given tooth and its surrounding gingiva illustrating anapproach of determining, by the processor of FIG. 5 , a plurality ofadditional reference vertices representative of a second verticalboundary for the positioning space for the orthodontic attachment ofFIG. 3B, in accordance with certain non-limiting embodiments of thepresent technology;

FIG. 11 depicts a schematic diagram of a plurality of patterns availablefor selection, by the processor of FIG. 5 , for defining a shape of thepositioning space for the orthodontic attachment of FIG. 3B on thesurface of the given tooth, in accordance with certain non-limitingembodiments of the present technology;

FIGS. 12A and 12B depict schematic diagrams of one approach to fitting,by the processor of FIG. 5 , a given pattern of the plurality ofpatterns of FIG. 11 within the surface of the 3D digital model of thegiven tooth to define the positioning space for the orthodonticattachment of FIG. 3B on the surface of the given tooth, in accordancewith certain non-limiting embodiments of the present technology;

FIGS. 13A and 13B depict schematic diagrams of another approach tofitting, by the processor of FIG. 5 , a given pattern of the pluralityof patterns of FIG. 11 within the surface of the 3D digital model of thegiven tooth to define the positioning space for the orthodonticattachment of FIG. 3B on the surface of the given tooth, in accordancewith certain non-limiting embodiments of the present technology;

FIG. 14A depicts a schematic diagram of a cut line defining an updatedprofile of an open edge of the orthodontic appliance of FIGS. 2A and 2B,by the processor of FIG. 5 , in the 3D digital model of the lower archform of FIG. 6 , based on the data of the positioning space of FIGS.12A, 12B, 13A, and 13B, allowing accommodating the orthodonticattachment 304, in accordance with certain non-limiting embodiments ofthe present technology;

FIG. 14B depicts a schematic diagram of the cut line of FIG. 14A beingembossed in a body of the 3D digital model of the lower arch form ofFIG. 6 , which can be used as a mold for producing the orthodonticappliance of FIGS. 2A and 2B, in accordance with certain non-limitingembodiments of the present technology; and

FIG. 15 depicts a flowchart diagram of a method for determining apositioning of the orthodontic attachment of FIG. 3B on the surface ofthe given tooth, in accordance with certain non-limiting embodiments ofthe present technology.

It should be noted that, unless otherwise explicitly specified herein,the drawings are not to scale.

DETAILED DESCRIPTION

Certain aspects and embodiments of the present technology are directedto methods of and systems for determining a position for an orthodonticattachment (such as an orthodontic attachment configured to retain anorthodontic elastic, for example), and based on the determined position,determining a shape for an orthodontic appliance, such as braces or analigner, which can be applied to subject's teeth concurrently with theorthodontic attachment.

More specifically, certain aspects and embodiments of the presenttechnology comprise a computer-implemented method of determining, basedon a 3D digital model of a subject's arch form, including a given tooth,a work area on a surface of the given tooth where the orthodonticattachment can be positioned. Further, the present methods are directedto determining a specific reference point within the work area, which isused in positioning the orthodontic attachment on the surface of thegiven tooth. For example, for orthodontic attachments which have a baseportion and a distal end portion with a protrusion to which the elasticcan be attached, the determined reference point can correspond to aposition of the protrusion when projected onto the surface of the giventooth.

Certain embodiments of the present technology minimize, reduce or avoidsome of the problems noted with the prior art. For example, implementingcertain embodiments of the present technology, may allow increasingeffectiveness of the orthodontic treatment including application of theabove-mentioned orthodontic appliances.

For example, the increased effectiveness of the orthodontic treatmentcan be achieved by determining such a position for the orthodonticattachment on the surface of the given tooth such that an actual valueof an additional force to be exerted on the at least one of thesubject's teeth by the orthodontic elastic would more preciselycorrespond to a predetermined value of the additional force required toattain the normal occlusion between the upper and lower teeth of thesubject.

In another example, the increased effectiveness of the orthodontictreatment can also be achieved by determining the position for theorthodontic attachment on the surface of the given tooth in such a waythat a concurrent application of the orthodontic appliance and theorthodontic attachment would allow for a better wear comfort thereof forthe subject, which may thus increase subject's adherence to theorthodontic treatment.

Orthodontic Treatment

With initial reference to FIG. 1 , there is depicted a perspective viewof a lower arch form 10 and an upper arch form 11 of the subject (notdepicted), to which certain aspects and non-limiting embodiments of thepresent technology may be applied.

As it can be appreciated, the lower arch form 10 includes lower teeth 12and a lower gingiva 14; and the upper arch form 11 includes upper teeth13 and upper gingiva 16. Further, in the depicted embodiments of FIG. 1, positions of at least some of the lower teeth 12 within the lower archform 10 and those of the upper teeth 13 within the upper arch form 11may be indicative of certain orthodontic disorders of the subject. Forexample, at least a given lower tooth 15 and a given upper tooth 17 aremisaligned within a respective one of the lower arch form 10 and theupper arch form 11. Further, as the given lower tooth 15 is abnormallyembedded within the lower teeth 12 while the given upper teeth 13abnormally protrudes over opposing ones of the lower teeth 12, themisalignment thereof may affect the bite of the teeth, or, in otherwords, cause a malocclusion—that is, an irregular spatialrelationship—between the lower teeth 12 and the upper teeth 13.

Other malocclusions (not depicted) associated with misalignment of lowerteeth 12 relative to each other and the upper teeth 13, according tocertain non-limiting embodiments of the present technology, may include,without limitation: overbites, underbites, crossbites, openbites,crowding of some of the lower teeth 12 and the upper teeth 13, midlineshift therebetween, and others.

In some non-limiting embodiments of the present technology, forresolving the above-mentioned malocclusions, an orthodontic treatmentmay be provided to the subject.

In some non-limiting embodiments of the present technology, theorthodontic treatment may comprise applying an orthodontic appliance tothe teeth of the subject. Generally speaking, the orthodontic appliancemay be configured to exert a respective predetermined force onto atleast some of the lower teeth 12 and the upper teeth 13—such as thegiven lower tooth 15 and the given upper tooth 17, causing them to movetowards an aligned position, thereby restoring the normal occlusion ofthe lower teeth 12 relative to upper teeth 13 of the subject. Morespecifically, in the depicted embodiments of FIG. 1 , the orthodonticappliance may be configured to cause the given lower tooth 15 to moveoutwardly between lower teeth adjacent thereto; and further causeclockwise rotation thereof. Further, the orthodontic appliance may beconfigured to cause the given upper tooth 17 to move inwardly. Invarious non-limiting embodiments of the present technology, theorthodontic appliance may comprise orthodontic appliances of differenttypes, shapes, sizes and configurations, such as those including,without limitation, aligners, brackets, multi-strand wires, strips,retainers, and plates.

In some non-limiting embodiments of the present technology, theorthodontic appliance may be selected, in the course of the orthodontictreatment to correct a respective malocclusion. For example, in somenon-limiting embodiments of the present technology, the orthodonticappliance may include a bracket system including: (i) brackets to beattached to at least some of the lower teeth 12 and/or the upper teeth13; and (ii) a wire typically produced from a shape memory alloy, suchas Nitinol™, as an example, that is received in the brackets of thelower teeth 12 or the upper teeth 13.

In specific non-limiting embodiments of the present the presenttechnology, the orthodontic appliance may include at least one aligner.With reference to FIGS. 2A and 2B, there is depicted an aligner 20applied to at least some of the lower teeth 12, in accordance withcertain non-limiting embodiments of the present technology. The aligner20 comprises an inner surface 22 and an outer surface 24. The innersurface 22 defines a channel 26, which is configured, in somenon-limiting embodiments of the present technology, for receiving crownportions of at least some of the lower teeth 12, such as the given lowertooth 15. However, in other non-limiting embodiments of the presenttechnology, the channel 26 of the aligner 20 may be configured toreceive crown portions of all of the lower teeth 12. At least one edge,such as a front edge 28 (also referred to herein as an “open edge”), ofthe channel 26 is shaped for following a gum line (not separatelynumbered) along the lower gingiva 14.

It will be appreciated that, in accordance with certain non-limitingembodiments of the present technology, the aligner 20 may be used fortreating different teeth malocclusions, including but not limited to oneor more of: closing interdental spaces (“space closure”),creating/widening interdental spaces, tooth rotation, toothintrusion/extrusion, and tooth translation, to name a few. It shouldfurther be noted that in certain non-limiting embodiments of the presenttechnology, applying the aligner 20 to the lower teeth 12 may furtherinclude applying specific attachments thereto.

As may become apparent, the aligner 20 may be designed in such a waythat its inner surface 22 is configured to impose respective forces onone or more of the lower teeth 12 to obtain a desired position of thelower teeth 12 at a given stage of the orthodontic treatment.

Needless to say that, although in the depicted embodiments of FIGS. 2Aand 2B, the aligner 20 is configured to be applied onto the lower teeth12, in other non-limiting embodiments of the present technology, arespective configuration of the aligner 20 may be applied to the upperteeth 13 of the subject for treating misalignment of at least somethereof—such as the given upper tooth 17. By so doing, the desiredocclusion between the lower teeth 12 and the upper teeth 13 may beattained.

According to certain non-limiting embodiments of the present technology,the aligner 20 may be made of a polymer, such as a thermoplasticmaterial. In other non-limiting embodiments of the present technology,the aligner 20 may be made of poly-vinyl chloride (PVC). In yet othernon-limiting embodiments of the present technology, the aligner 20 maybe made of polyethylene terephthalate glycol (PETG). Other suitablematerials can also be used to form the aligner 20.

In some non-limiting embodiments of the present technology, the aligner20 may be manufactured using additive manufacturing techniques, such as3D printing techniques where the aligner 20 is formed by printingaccording to a pre-generated 3D representation thereof.

In other non-limiting embodiments of the present technology, the aligner20 may be produced by a thermoforming process where (1) an unfinishedaligner is produced, using a preform, on a respective aligner mold (notdepicted) associated with a respective stage of the orthodontictreatment, which is configured to shape the inner surface 22 of thealigner 20; and (2) the unfinished aligner is cut along a predeterminedcut line to remove excess material therefrom, thereby producing thealigner 20, the predetermined cut line defining the at least one edge ofthe channel 26 of the aligner 20, such as that of the front edge 28.

In specific non-limiting embodiments of the present technology, thealigner 20 may be manufactured in accordance with one or more methodsdescribed in a co-owned U.S. Pat. No. 11,191,618-B1, issued on Dec. 7,2021, and entitled “SYSTEMS AND METHODS FOR FORMING A DENTALAPPLIANCE,”, the content of which is incorporated herein by reference inits entirety.

Also, in certain cases, to attain a desired relative position betweenthe lower and upper arch forms 10, 11 and hence the lower teeth 12 andupper teeth 13, it may be advantageous to use an other orthodonticappliance (also referred to herein as an “auxiliary orthodonticappliance”) to a surface of at least one of the subject's teeth, such asthe given lower tooth 15. In some non-limiting embodiments of thepresent technology, the other orthodontic appliance can comprise anorthodontic elastic, made of elastic material, such as rubber, latex,and the like, configured to be attached to an orthodontic attachment onthe lower teeth 12 and another orthodontic attachment on the upper teeth13, the orthodontic elastic being stretched between the upper and thelower tooth for re-positioning a relative position between the lowerteeth 12 and the upper teeth 13.

With reference to FIGS. 3A and 3B, there is depicted a schematic diagramillustrating an orthodontic elastic 302 extending between the lowerteeth 12 and the upper teeth 13, in addition to the aligner 20, inaccordance with certain non-limiting embodiments of the presenttechnology.

As it can be appreciated from FIG. 3A, according to certain non-limitingembodiments of the present technology, the orthodontic elastic 302 cancomprise a band which is looped around orthodontic attachments attachedto respective ones of the lower teeth 12 and the upper teeth 13, such asan orthodontic attachment 304 attached to the given lower tooth 15, asan example.

To the upper teeth 13, in one example, the orthodontic elastic 302 canbe attached via an attachment similar to the orthodontic attachment 304(not depicted in FIG. 3A). However, in another example depicted in FIG.3A, the orthodontic elastic 302 can be attached to the upper teeth 13via a specific hook defined within a body of the aligner 20. Anelasticity value of the material of the orthodontic elastic 302 and asize thereof (such as a diameter) define a force to be applied to thelower and upper teeth 12, 13, which can thus be selected such that thelower teeth 12 and the upper teeth 13, while at rest, are retained in adesired occlusion (such that corresponding to the normal occlusiontherebetween, for example).

Further, it is not limited how the orthodontic attachment 304 can beimplemented. In a specific non-limiting example depicted in FIG. 3B, theorthodontic attachment 304 can include at least (i) a base portion 306configured for attaching to the surface of the given lower tooth 15;(ii) a neck portion 308, around which the orthodontic elastic 302 can belooped; and (iii) a head portion 310 configured for retaining theorthodontic elastic 302 on the neck portion 308. For example, theorthodontic attachment 304 can be produced from a metal, such as astainless-steel alloy.

It should be noted that in various non-limiting embodiments of thepresent technology, depending on a particular application, theorthodontic attachment 304 can have different configurations including,without limitation, a different form factor of at least one of the baseportion 306, the neck portion 308, and the head portion 310; a differentmaterial thereof; different dimensions thereof, and the like. Forexample, in specific non-limiting embodiments of the present technology,instead of having the neck portion 308 and the head portion 310, toretain the orthodontic elastic 302, the orthodontic attachment 304 caninclude a hook attached to the base portion 306.

Further, as it can also be appreciated from FIG. 3A, to accommodate theorthodontic attachment 304 on the surface of the given lower tooth 15,the front edge 28 of the aligner 20 may need to be modified to define arespective cut-out therein allowing for concurrent application of boththe aligner 20 and the orthodontic attachment 304 to the given lowertooth 15.

However, a coupling location of the base portion 306 of the orthodonticattachment 304 to the surface of the given lower tooth 15 should becarefully determined as it may affect the actual value of the force tobe applied to the lower and upper teeth 12, 13 by the orthodonticelastic 302 lowering an overall efficacy of the orthodontic treatment.For example, failing to determine a correct coupling position for theorthodontic attachment 304 may further result in the orthodontic elastic302 connected thereto imposing an insufficient amount of the elasticforce to the lower teeth 12. In another example, an uncarefully selectedcoupling position for the orthodontic attachment 304 can cause theorthodontic elastic 302 to impose a greater amount of the elastic forceto the lower teeth 12, which can cause damage to the lower arch form 10or even to an entire lower jaw of the subject (not separately numbered),such as damage to at least one mandibular head thereof; or an additionalmisalignment between the lower teeth 12 and the upper teeth 13.

In yet another example, notwithstanding the above, the selected couplingposition for the orthodontic attachment 304 can cause wear discomfort tothe subject. This in turn can affect subject's adherence to theorthodontic treatment, which may thus result in lowered efficacythereof.

Thus, the developers of the present technology have devised methods andsystems for determining an optimal coupling position for the orthodonticattachment 304. More specifically, the present methods and systems aredirected to determining the coupling position of the orthodonticattachment 304 within a work area (such as a work area 910 depicted inFIG. 9B) specifically determined on the surface of the given lower tooth15, using, for example a 3D digital model thereof.

Further, according to certain non-limiting embodiments of the presenttechnology, the present methods are directed to obtaining an indicationof a respective pattern (such as a given pattern 1104 depicted in FIG.11 ), corresponding to a particular geometry of the base portion 306 ofthe orthodontic attachment 304, and thus representative of a shape of apositioning space (such as a positioning space 1210 depicted in FIG.12B) within the work area 910 for positioning thereon the orthodonticattachment 304. Further, the methods include fitting the given pattern1104 within the work area 910, which can include: (i) determining,within the work area 910, a reference vertex of the 3D digital modelrepresentative of a boundary of the positioning space towards the crownportion of the given lower tooth 15; and (ii) additional referencevertices representative of a boundary of the positioning space towardsthe lower gingiva 14. Further, the present methods are directed tofitting, such as by scaling, the given pattern 1104 between the sodetermined reference vertices on the 3D digital model of the given lowertooth 15, thereby determining the positioning space 1210 for theorthodontic attachment 304 on the surface thereof.

Further, considering the positioning space 1210 on the surface of thegiven lower tooth 15, a configuration of the respective cut-out on thebody of the aligner 20 can be determined, defining an updated profile ofthe front edge 28 thereof. The updated profile of the front edge 28 canthus enable simultaneous use of the aligner 20 and the orthodonticattachment 304 on the lower teeth 12.

Therefore, the positioning space 1210 for the orthodontic attachment 304can allow for a more optimal amount of the elastic force imposed by theorthodontic elastic 302 as well as for improved wear comfort of thealigner 20 thus produced based on data of the updated profile of thefront edge 28 thereof. How the positioning space 1210 can be determined,in accordance with certain non-limiting embodiments of the presenttechnology, will be described below with reference to FIGS. 6 to 13B.

System

With reference to FIGS. 4 and 5 , there is depicted a schematic diagramof a system 400 suitable for determining a position for an orthodonticattachment, such as the orthodontic attachment 304 mentioned above, inaccordance with certain non-limiting embodiments of the presenttechnology.

It is to be expressly understood that the system 400 as depicted ismerely an illustrative implementation of the present technology. Thus,the description thereof that follows is intended to be only adescription of illustrative examples of the present technology. Thisdescription is not intended to define the scope or set forth the boundsof the present technology. In some cases, what is believed to be helpfulexamples of modifications to the system 400 may also be set forth below.This is done merely as an aid to understanding, and, again, not todefine the scope or set forth the bounds of the present technology.These modifications are not an exhaustive list, and, as a person skilledin the art would understand, other modifications are likely possible.Further, where this has not been done (i.e., where no examples ofmodifications have been set forth), it should not be interpreted that nomodifications are possible and/or that what is described is the solemanner of implementing that element of the present technology. As aperson skilled in the art would understand, this is likely not the case.In addition, it is to be understood that the system 400 may provide incertain instances simple implementations of the present technology, andthat where such is the case they have been presented in this manner asan aid to understanding. As persons skilled in the art would furtherunderstand, various implementations of the present technology may be ofa greater complexity.

In certain non-limiting embodiments of the present technology, thesystem 400 of FIG. 4 comprises a computer system 410. The computersystem 410 may be configured, by pre-stored program instructions, todetermine, based on image data associated with the subject, such as the3D digital model of the given lower tooth 15, the position for theorthodontic attachment 304 on the surface of the given lower tooth 15,and further using data of the position of the orthodontic attachment304, determine a cut line defining a configuration of at least an edgeof at least one wall of the channel 26, such as the front edge 28, ofthe aligner 20. In additional non-limiting embodiments of the presenttechnology, the computer system 410 may further be configured to produceat least one configuration of the aligner 20 based on the so plannedorthodontic treatment.

To that end, in some non-limiting embodiments of the present technology,the computer system 410 may be configured to receive image datapertaining to the subject or to a given stage of the orthodontictreatment. According to some non-limiting embodiments of the presenttechnology, the computer system 410 may receive the image data via localinput/output interface (such as USB, as an example, not separatelydepicted). In other non-limiting embodiments of the present technology,the computer system 410 may be configured to receive the image data overa communication network 425, to which the computer system 410 iscommunicatively coupled.

In some non-limiting embodiments of the present technology, thecommunication network 425 is the Internet and/or an Intranet. Multipleembodiments of the communication network may be envisioned and willbecome apparent to the person skilled in the art of the presenttechnology. Further, how a communication link between the computersystem 410 and the communication network 425 is implemented will depend,inter alia, on how the computer system 410 is implemented, and mayinclude, but is not limited to, a wire-based communication link and awireless communication link (such as a Wi-Fi communication network link,a 3G/4G communication network link, and the like).

It should be noted that the computer system 410 can be configured forreceiving the image data from a vast range of devices. Some of suchdevices can be used for capturing and/or processing data pertaining tomaxillofacial and/or cranial anatomy of the subject. In certainembodiments, the image data received from such devices is indicative ofproperties of anatomical structures of the subject, including: teeth,intraoral mucosa, maxilla, mandible, temporomandibular joint, and nervepathways, among other structures. In some non-limiting embodiments ofthe present technology, at least some of the image data is indicative ofproperties of external portions of the anatomical structures, forexample dimensions of a gingival sulcus, and dimensions of an externalportion of a tooth (such as a crown portion of the given lower tooth 15,not separately numbered) extending outwardly of the gingival sulcus. Insome embodiments, the image data is indicative of properties of internalportions of the anatomical structures, for example, volumetricproperties of bone surrounding an internal portion of the tooth (forexample, a root portion of the given lower tooth 15, not depicted)extending inwardly of the gingival sulcus. Under certain circumstances,such volumetric properties may be indicative of periodontal anomalieswhich may be factored into an orthodontic treatment plan. In somenon-limiting embodiments of the present technology, the image dataincludes cephalometric image datasets. In some embodiments, the imagedata includes datasets generally intended for the practice ofendodontics. In some embodiments, the image data includes datasetsgenerally intended for the practice of periodontics.

Further, as noted above, after the determining the tooth trajectory forthe given lower tooth 15, in some non-limiting embodiments of thepresent technology, the system 400 may be configured, based on arespective 3D digital model of the lower arch form 10, determine theorthodontic treatment for the subject including forces to be appliedonto the given lower tooth 15 to cause the given lower tooth 15 to moveto the target position thereof. In specific non-limiting embodiments ofthe present technology, the orthodontic treatment may be determined (forexample, by a processor 550 depicted in FIG. 5 ) as described in aco-owned U.S. Pat. No. 10,993,782-B1 issued on May 4, 2021, and entitled“SYSTEMS AND METHODS FOR DETERMINING A TOOTH TRAJECTORY”, a content ofwhich is hereby incorporated by reference in its entirety.

In alternative non-limiting embodiments of the present technology, thecomputer system 410 may be configured to receive the image dataassociated with the subject directly from an imaging device 430communicatively coupled thereto. Broadly speaking, the processor 550 maybe configured to cause the imaging device 430 to capture and/or processthe image data of the lower teeth 12 and the periodontium (not depicted)of the subject. In certain non-limiting embodiments of the presenttechnology, the image data may include, for example, one or more of: (1)images of external surfaces of respective crown portions of the lowerteeth 12, (2) images of an external surface of the periodontiumincluding those of the lower gingiva 14, the alveolar mandibular bone(not depicted), and images of superficial blood vessels and nervepathways associated with the lower teeth 12; and (3) images of an oralregion. By doing so, the imaging device 430 may be configured, forexample, to capture image data of the lower arch form 10 of the subject.In another example, the imaging device may also be configured to captureand/or process image data of an upper arch form (not depicted)associated with the subject without departing from the scope of thepresent technology. It should be noted that the image data may includetwo-dimensional (2D) data and/or three-dimensional data (3D). Further,in certain non-limiting embodiments of the present technology, the imagedata includes 2D data, from which 3D data may be derived, and viceversa.

In some non-limiting embodiments of the present technology, the imagingdevice 430 may comprise an intra-oral scanner enabling to capture directoptical impressions of each one of the lower arch form 10 and upper archform 11 of the subject.

In a specific non-limiting example, the intraoral scanner can be of oneof the types available from MEDIT, CORP. of 23 Goryeodae-ro 22-gil,Seongbuk-gu, Seoul, South Korea. It should be expressly understood thatthe intraoral scanner can be implemented in any other suitableequipment.

In yet other non-limiting embodiments of the present technology, theimaging device 430 can comprise a 3D laser scanner enabling to obtain arespective point cloud 3D digital model of each one of the lower archform 10 and the upper arch form 11—such as by scanning a mold thereofand thus registering three-dimensional coordinates of pointsrepresentative of the surface of the mold.

In a specific non-limiting example, the 3D laser scanner can be of oneof the types available from LASER DESIGN of 5900 Golden Hills Drive,Minneapolis, Minn. 55416. It should be expressly understood that thedesktop scanner can be implemented in any other suitable equipment.

Further, it is contemplated that the computer system 410 may beconfigured for processing of the received image data. The resultingimage data of each one of the lower arch form 10 and then upper archform 11 received by the computer system 410 is typically structured as abinary file or an ASCII file, may be discretized in various ways (e.g.,point clouds, polygonal meshes, pixels, voxels, implicitly definedgeometric shapes), and may be formatted in a vast range of file formats(e.g., STL, OBJ, PLY, DICOM, and various software-specific, proprietaryformats). Any image data file format is included within the scope of thepresent technology. For implementing functions described above, thecomputer system 410 may further comprise a corresponding computingenvironment.

Further, in certain non-limiting embodiments of the present technology,the system 400 may be configured to produced at least one configurationof the aligner 20 based on the planned orthodontic treatment asmentioned above. For example, in certain non-limiting embodiments of thepresent technology, the system 400 can be configured to produce anunfinished aligner (not depicted), for example, using a thermoprimingprocess, in which a preform aligner (not depicted) is shaped on the moldof the lower arch form 10. Further, the system 400 can be configured totrim excess material along the cut line to produce an edge of thealigner 20.

In some non-limiting embodiments of the present technology, the system400 can be configured to determine (or otherwise receive data indicativeof) the cut line and mark the cut line on the unfinished aligner. Tothat end, the system 400 may further comprise a marking subsystem 440.It is not limited how the marking subsystem 440 may be implemented;however, in various non-limiting embodiments of the present technology,the marking subsystem 440 may include a marking head 442 for applyingthe cut line onto the unfinished aligner and a first robotic arm (notdepicted) for holding and manipulating the unfinished aligner (notdepicted) around the marking head 442. In some non-limiting embodimentsof the present technology, the marking head 442 may further comprise acoloring material storage (not depicted) for storing a coloring material(such as ink, as an example) and a supply control block (not depicted).In some non-limiting embodiments of the present technology, the markinghead 442 may be implemented as a laser apparatus configurable to scorchthe cut line (not depicted) on the unfinished aligner (not depicted).

In certain non-limiting embodiments of the present technology, thesystem 400 may further be configured to detect the cut line applied onthe unfinished aligner and cut along the cut line to produce the aligner20. In this regard, the system 400 may further comprise a formingsubsystem 450. In some non-limiting embodiments of the presenttechnology, the forming subsystem 450 may include a second robotic arm(not depicted), at an end-effector of which there is installed a cameradevice 452. In some non-limiting embodiments of the present technology,the camera device 452 can be any appropriate digital camera configuredto detect the cut line applied by the marking subsystem 440 describedabove onto the unfinished aligner, including, for example, but notlimited to, a coupled-charged device camera (a CCD camera). Further, asmentioned above, the forming subsystem 450 may include the cuttingdevice 454. Non limiting examples of the cutting device 454 may includea laser-based cutting device, a mechanical cutting device such as usinga blade with a rotary or linear cutting action, and a water-jet basedcutting device, as an example.

In some non-limiting embodiments of the present technology, both themarking subsystem 440 and the forming subsystem 450 of the system 400may be implemented as described in a co-owned U.S. patent applicationSer. No. 16/704,718 filed on Dec. 5, 2019, entitled “SYSTEMS AND METHODSFOR FORMING PERSONALIZED DENTAL APPLIANCES”, the content of which ishereby incorporated by reference in its entirety.

Thus, the forming subsystem 450 may be configured to: (1) cause thecamera device 452 to move around the unfinished aligner (not depicted)with the cut line (not depicted) applied thereon to detect the cut lineand generating respective image data thereof; (2) receive the image dataof the cut line; and (3) based on the received image data of the cutline, cause cutting, by the cutting device 454 the unfinished aligneralong the cut line, thereby forming the aligner 20.

In other non-limiting embodiments of the present technology, the formingsubsystem 450 may be configured for cutting the unfinished alignerwithout requiring detection of the cut line. Instead, the determined cutline is used to guide the cutting—for example, based on received dataindicative of a position of the cut line within the unfinished aligner.In some non-limiting embodiments of the present technology, the dataindicative of the position of the cut line within the unfinished alignermay include at least one of: Cartesian coordinates; angular dataindicative of a cutting angle for cutting the unfinished aligner; and adistance from the cutting device 454, as an example.

Further, with reference to FIG. 5 , there is depicted a schematicdiagram of a computing environment 540 suitable for use with someimplementations of the present technology. The computing environment 540comprises various hardware components including one or more single ormulti-core processors collectively represented by the processor 550, asolid-state drive 560, a random-access memory 570 and an input/outputinterface 580. Communication between the various components of thecomputing environment 540 may be enabled by one or more internal and/orexternal buses 590 (e.g. a PCI bus, universal serial bus, IEEE 1394“Firewire” bus, SCSI bus, Serial-ATA bus, ARINC bus, etc.), to which thevarious hardware components are electronically coupled.

The input/output interface 580 allows enabling networking capabilitiessuch as wire or wireless access. As an example, the input/outputinterface 580 comprises a networking interface such as, but not limitedto, a network port, a network socket, a network interface controller andthe like. Multiple examples of how the networking interface may beimplemented will become apparent to the person skilled in the art of thepresent technology. For example, but without being limiting, theinput/output interface 580 may implement specific physical layer anddata link layer standard such as Ethernet, Fibre Channel, Wi-Fi™ orToken Ring™. The specific physical layer and the data link layer mayprovide a base for a full network protocol stack, allowing communicationamong small groups of computers on the same local area network (LAN) andlarge-scale network communications through routable protocols, such asIP.

According to implementations of the present technology, the solid-statedrive 560 stores program instructions suitable for being loaded into therandom-access memory 570 and executed by the processor 550, according tocertain aspects and embodiments of the present technology. For example,the program instructions may be part of a library or an application.

In some non-limiting embodiments of the present technology, thecomputing environment 540 is implemented in a generic computer system,which is a conventional computer (i.e. an “off the shelf” genericcomputer system). The generic computer system may be a desktopcomputer/personal computer, but may also be any other type of electronicdevice such as, but not limited to, a laptop, a mobile device, a smartphone, a tablet device, or a server.

As persons skilled in the art of the present technology may appreciate,multiple variations as to how the computing environment 540 can beimplemented may be envisioned without departing from the scope of thepresent technology.

Referring back to FIG. 4 , the computer system 410 has at least oneinterface device 420 for providing an input or an output to a user ofthe system 400, the interface device 420 being in communication with theinput/output interface 580. In the embodiment of FIG. 4 , the interfacedevice is a screen 422. In other non-limiting embodiments of the presenttechnology, the interface device 420 may be a monitor, a speaker, aprinter or any other device for providing an output in any form such asan image form, a written form, a printed form, a verbal form, a 3D modelform, or the like.

In the depicted embodiments of FIG. 4 , the interface device 420 alsocomprises a keyboard 424 and a mouse 426 for receiving input from theuser of the system 400. Other interface devices 420 for providing aninput to the computer system 410 can include, without limitation, a USBport, a microphone, a camera or the like.

The computer system 410 may be connected to other users, such as throughtheir respective clinics, through a server (not depicted). The computersystem 410 may also be connected to stock management or client softwarewhich could be updated with stock when the orthodontic treatment hasbeen determined and/or schedule appointments or follow-ups with clients,for example.

Image Data

As alluded to above, according to certain non-limiting embodiments ofthe present technology, the processor 550 may be configured to: (1)receive the respective 3D digital model of a current configuration ofthe lower arch form 10 including the 3D digital model of the giventooth; (2) determine, based on the respective 3D digital model, theposition for the orthodontic attachment 304 on the surface of the giventooth; and optionally (3) and determine, based on the position of theorthodontic attachment, a configuration of the cut line for further usein producing the respective configuration of the aligner 20, asmentioned above.

With reference to FIG. 6 , there is schematically depicted a perspectiveview of an arch form 3D digital model 600 of the lower arch form 10used, by the processor 550, for determining the position for theorthodontic attachment 304 on the surface of the given lower tooth 15,in accordance with certain non-limiting embodiments of the presenttechnology.

In some non-limiting embodiments of the present technology, theprocessor 550 may be configured to receive, from the imaging device 430,the arch form 3D digital model 600 comprising a respective plurality ofmesh elements (not depicted) representative of a surface of the lowerarch form 10. For example, the imaging device 430 can be configured togenerate the plurality of mesh elements including, without limitation,triangular mesh elements, quadrilateral mesh elements, convex polygonalmesh elements, or even concave polygonal mesh elements, as an example,without departing from the scope of the present technology.

However, in those embodiments where the imaging device 430 is the 3Dlaser scanner, the arch form 3D digital model 600 comprises a respective3D point cloud representative of the surface of the lower arch form 10.

As noted above, according to the non-limiting embodiments of the presenttechnology, the lower arch form 10 comprises the lower teeth 12 (alsoreferred to herein as “mandibular teeth”) and the lower gingiva 14. Asit can be appreciated, the lower teeth 12 are represented, in the archform 3D model 600, by respective crown portions associated therewith.

It should be expressly understood that, although the description hereinbelow will be given in respect of the lower arch form 10 of the subject(and associated therewith the lower teeth 12 and the lower gingiva 14)for the sake of clarity and simplicity thereof, and in no way as alimitation, the non-limiting embodiments of the present technology canalso apply to the upper teeth 13 of the subject with certainalterations, which will be explicitly indicated below where necessary.

Further, according to certain non-limiting embodiments of the presenttechnology, based on the arch form 3D digital model 600, the processor550 can be configured to generate a 3D digital model of the given lowertooth 15. With continued reference to FIG. 6 and with reference to FIG.7 , there is depicted a schematic diagram of a tooth 3D digital model700 of the given lower tooth 15, in accordance with certain non-limitingembodiments of the present technology.

In some non-limiting embodiments of the present technology, to generatethe tooth 3D digital model 700, the processor 550 can be configured toisolate a portion of the arch form 3D digital model 600 representativeof the crown portion of the given lower tooth 15.

How the processor 550 can be configured to isolate the portion of thearch form 3D digital model 600 representative of the crown portion ofthe lower tooth 15 is not limited; and, in some non-limiting embodimentsof the present technology, the processor 550 can be configured to apply,to the arch form 3D digital model 600, one or more automatic toothsegmentation approaches described in a co-owned U.S. Pat. No.10,950,061-B1 issued on Mar. 16, 2021, entitled “SYSTEMS AND METHODS FORPLANNING AN ORTHODONTIC TREATMENT”, content of which is incorporatedherein by reference in its entirety.

More specifically, to generate the tooth 3D digital model 700 of thegiven lower tooth 15, the processor 550 may be configured to: (i)acquire the arch form 3D digital model 600 of the lower arch form 10 ofthe subject, the arch form 3D digital model 600 comprising a definedportion forming part of a surface of the given lower tooth 15, and atleast one undefined portion not forming part of the surface of the givenlower tooth 15; the arch form 3D digital model 600 comprising theplurality of mesh elements having a plurality of vertices comprising:constrained vertices associated with the defined portion, eachconstrained vertex having a normal constrained vertex vector;unconstrained vertices initially associated with the undefined portion,each unconstrained vertex having a normal unconstrained vertex vector;(ii) generate a set of confirmed constrained vertices, including theconstrained vertices associated with the defined portion, representativeof the crown portion of the given lower tooth 15 by: (iii) iteratively,for a given constrained vertex, identifying at least one associatedunconstrained vertex which is adjacent to the given constrained vertexin the plurality of mesh elements; (iv) determining an angulardifference between the normal constrained vertex vector of the givenconstrained vertex and the normal unconstrained vertex vector of the atleast one associated unconstrained vertex; (v) in response to theangular difference being equal to or below a predetermined thresholdvalue: identifying the at least one associated unconstrained vertex tobe a constrained vertex associated with the defined portion forinclusion in the set of confirmed constrained vertices; (vi) in responseto the angular difference being above the predetermined threshold value:identifying the at least one associated unconstrained vertex to be anunconstrained vertex associated with the undefined portion for exclusionfrom the set of confirmed constrained vertices.

Further, according to certain non-limiting embodiments of the presenttechnology, the processor 550 can be configured to determine, based onthe arch form 3D digital model 600 of the lower arch form 10, atooth-gingiva segmentation loop 602 indicative of a boundary between thecrown portion of the given lower tooth 15 and the lower gingiva 14.

In some non-limiting embodiments of the present technology, theprocessor 550 can be configured to determine the tooth-gingivasegmentation loop 602 as a closed curve extending along an edge of theportion of the arch form 3D digital model 600 representative of thecrown portion of the given lower tooth 15, determined as described abovewith reference to FIG. 7 .

In other non-limiting embodiments of the present technology, theprocessor 550 may be configured to obtain the tooth-gingiva segmentationloop 602 having been previously generated by third-party software, basedon the arch form 3D digital model 600, and data indicative thereof mayhave been stored in a data format, in which the processor 550 may beconfigured to receive it, for example, via the input/output interface580.

In yet other non-limiting embodiments of the present technology, thetooth-gingiva segmentation loop 602 may be generated manually, forexample, by a practicing clinician involved in the determining theorthodontic treatment. For example, a practicing clinician involved inthe determining the orthodontic treatment for the subject may manuallyapply the tooth-gingiva segmentation loop 602 onto the arch form 3Ddigital model 600, using respective suitable software, and the processor550 may further be configured to receive the arch form 3D digital model600, and detect the tooth-gingiva segmentation loop 602 applied thereon.

Further, as will become apparent from the description providedhereinbelow, in at least some non-limiting embodiments of the presenttechnology, the determining the position for the orthodontic attachment304 on the surface of the given lower tooth 15 can include determining,in the tooth 3D digital model, a respective tooth reference pointtherewithin indicative of a position thereof relative to other ones ofthe lower teeth 12, such as a tooth reference point 704. It is notlimited how the tooth reference point 704 can be determined, and invarious non-limiting embodiments of the present technology, can comprisea specific point equally representative of each one of the lower teeth12, such as that representative of a common anatomical feature of eachone of the lower teeth 12, including, for example, a middle point of arespective crown portion thereof, a cusp tip thereof, one ofdevelopmental grooves thereof, and the like.

For example, in some non-limiting embodiments of the present technology,the tooth reference point 704 can include a geometric center of massassociated with the given lower tooth 15, such as that determinedconsidering the given lower tooth 15 as a solid physical object.

However, in other non-limiting embodiments of the present technology,the center point 704 can be determined as being a center of resistance(CR) point associated with the given lower tooth 15. For example, alocation of the CR point within the given lower tooth 15 can bedetermined based on the tooth 3D digital model 700 as described in aco-owned U.S. Pat. No. 10,856,954-B1 issued on Dec. 8, 2020 and entitled“SYSTEMS AND METHODS FOR DETERMINING TOOTH CENTER OF RESISTANCE”, thecontent of which is hereby incorporated by reference in its entirety.More specifically, in these embodiments, the processor 550 can beconfigured to: (i) obtain the tooth 3D digital model 700; (ii) identifyan internal tooth reference point within the tooth 3D digital model 700,the internal tooth reference point corresponding to a mesiodistal centerof the crown portion of the given lower tooth 15, the identifying theinternal tooth reference point comprising: obtaining a mesial point on amesial side of the crown portion, and a distal point on a distal side ofthe crown portion; generating a mesiodistal line joining the mesialpoint and the distal point; identifying the mesiodistal center as amidpoint on the mesiodistal line; (iii) determine a reference plane inthe tooth 3D digital model 700, the reference plane being perpendicularto the mesiodistal line and extending through the mesiodistal center;(iv) determine an intersection curve based on an intersection of thereference plane and the tooth 3D digital model 700, the intersectioncurve following a shape of the surface of the tooth 3D digital model 700at the reference plane; (v) determine a tooth axis of the given lowertooth 15 based on the intersection curve; (vi) determine a crown heightof the crown portion of the given tooth based on the determined toothaxis; and (vii) determine the CR point of the given lower tooth 15 basedon the determined crown height and the determined tooth axis.

Thus, having obtained the above data, the processor 550 can beconfigured to determine the position for the orthodontic attachment 304on the surface of the given lower tooth 15, which will now be describedwith reference to FIGS. 9A to 13B.

Determining the Work Area

First, as mentioned above, according to certain non-limiting embodimentsof the present technology, the processor 550 can be configured todetermine the work area 910 on the surface of the given lower tooth 15,within which the orthodontic attachment 304 would be positioned. In somenon-limiting embodiments of the present technology, the processor 550can be configured to determine the work area 910 as corresponding to anarea on the surface of the given lower tooth 15 having a predeterminedcurvature.

To that end, according to certain non-limiting embodiments of thepresent technology, the processor 550 can be configured to determine ajaw curve associated with the lower teeth 12. With reference to FIG. 8 ,there is depicted a top view of the arch form 3D digital model 600illustrating an approach for determining, by the processor 550, a lowerjaw curve 802, in accordance with certain non-limiting embodiments ofthe present technology.

According to certain non-limiting embodiments of the present technology,the processor 550 can be configured to determine the lower jaw curve 802by sequentially joining respective tooth reference points associatedwith each one of the lower teeth 12, such as the tooth reference point704 associated with given lower tooth 15, as described above.

It should be noted that it is not limited how the processor 550 can beconfigured to join the respective tooth reference points. For example,in some non-limiting embodiments of the present technology, theprocessor 550 can be configured to join the respective tooth referencepoints associated with the lower teeth 12 with linear segments. However,in other non-limiting embodiments of the present technology, theprocessor 550 can be configured to join the respective tooth referencepoints with curve segments, such as those defined by a polynomialfunction, including, for example, a spline function, a Bezier curvefunction, and the like. In additional non-limiting embodiments of thepresent technology, after joining the respective tooth reference points,the processor 550 can further be configured to smooth jointstherebetween using any suitable curve smoothing algorithm, such as alocal regression smoothing algorithm, a Kernel smoothing algorithm, andthe like.

Further, to analyze the curvature of the side surface of the given lowertooth 15, the processor 550 can be configured to determine, for each oneof the lower teeth 12 a respective reference plane intersecting thelower jaw curve 802 in the respective tooth reference point—such as areference plane 804 extending through the tooth reference point 704associated with the given lower tooth 15. For example, in somenon-limiting embodiments of the present technology, the processor 550can be configured to determine the reference plane 804 as beingperpendicular to the lower jaw curve 802 (or to a tangent thereof at thereference point 704).

Further, the processor 550 can be configured to analyze the curvature ofthe side surface of the given lower tooth 15 relative to the referenceplane 804. More specifically, depending on a particular side of thegiven lower tooth 15 onto which the orthodontic attachment 304 is to beattached thereto, such as a buccal or lingual side thereof, theprocessor 550 can be configured to determine an angular differencebetween the reference plane 804 and a respective normal vector definedat a each vertex of the tooth 3D digital model 700 on a buccal orlingual side thereof relative to the lower jaw curve 802.

With reference to FIGS. 9A and 9B, there is depicted a schematic diagramof a top and side view of the tooth 3D digital model 700 illustrating anapproach for determining, by the processor 550, the work area 910 on thesurface of the given lower tooth 15, in accordance with certainnon-limiting embodiments of the present technology.

More specifically, in some non-limiting embodiments of the presenttechnology, the processor 550 can be configured to determine arespective angular difference 906 between a normal vector 904 to thesurface of the tooth 3D digital model 700 at a given vertex 902representative of the buccal side of the given lower tooth 15, forexample. Further, in response to determining that the respective angulardifference 906 is greater than a predetermined angular differencethreshold value (being, for example, 60 or 75 degrees), the processor550 can be configured to remove the given vertex 902 from furtherconsideration, that is, reject from inclusion thereof in verticesrepresentative of the work area 910. By contrast, in response todetermining that the respective angular difference 906 is lower than orequal to the predetermined angular difference threshold, the processor550 can be configured to determine the given vertex 902 as beingrepresentative of the work area 910. Thus, by analyzing the curvature ofthe buccal side of the given lower tooth 15 in a such a way, theprocessor 550 can be configured to determine the work area 910 forpositioning the orthodontic attachment 304 therewithin.

Determining a Position for the Attachment

Further, the processor 550 can be configured to determine, within thework area 910, the positioning space 1210 on which the orthodonticattachment 304 is to be attached to the given lower tooth 15. To thatend, the processor 550 can be configured to: (1) determine a firstvertical boundary for the positioning space 1210; (2) determine a secondvertical boundary for the positioning space 1210; (3) retrieve arespective pattern representative of a shape of the base portion 306 ofthe orthodontic attachment 304; and (4) fit the respective patternwithin the work area 910 between the first vertical boundary and thesecond vertical boundary.

According to certain non-limiting embodiments of the present technology,the processor 550 can be configured to determine the first verticalboundary as a boundary towards the crown portion of the given lowertooth 15, that is, in the orientation of FIG. 9B, the first verticalboundary can be defined as being an upper boundary for the positioningspace.

In this regard, with continued reference to FIG. 9B, according tocertain non-limiting embodiments of the present technology, theprocessor 550 can be configured to determine, within the work area 910,a reference vertex 915 representative of the first vertical boundary ofthe positioning space 1210. It is not limited how the processor 550 canbe configured to determine the reference vertex 915. For example, theprocessor 550 can be configured to determine the reference vertex 915 asbeing a center of the work area 910.

However, in other non-limiting embodiments of the present technology, todetermine the reference vertex 915, the processor 550 can be configuredto: (i) identify a plurality of contour vertices 912 defining a contourof the work area 910; and (ii) determine the reference vertex 915 asbeing a vertex of the work area 910 that is most distant from all of theplurality of contour vertices 912. In some non-limiting embodiments ofthe present technology, the processor 550 can be configured to determinesuch a vertex by determining a vertex of the work area 910 from which asummation of all distance values therefrom to each one of the pluralityof contour vertices 912, such as a given distance value 916, is maximum.To that end, the processor 550 can be configured to apply a Dijkstraalgorithm, as an example.

Further, according to certain non-limiting embodiments of the presenttechnology, based on a predetermined rule, the processor 550 can beconfigured to determine the second vertical boundary for the positioningspace 1210 as corresponding to the tooth-gingiva segmentation loop 602associated with the given lower tooth 15, that is, in the orientation ofFIG. 9B, the second vertical boundary can be defined as a lower boundaryfor the positioning space 1210 for the orthodontic attachment 304.

With reference to FIGS. 10A and 10B, there is depicted a top view of thetooth-gingiva segmentation loop 602 illustrating an approach ofdetermining, by the processor 550, a plurality of additional referencevertices 1006 representative of the second vertical boundary for thepositioning space 1210 for the orthodontic attachment 304, in accordancewith certain non-limiting embodiments of the present technology.

First, in some non-limiting embodiments of the present technology, theprocessor 550 can be configured to identify, along the tooth-gingivasegmentation loop 602, portions thereof that are common to teethneighboring the given lower tooth 15—such as a given common portion 1002of the tooth-gingiva segmentation loop 602.

For example, in some non-limiting embodiments of the present technology,the processor 550 can be configured to determine the given commonportion 1002 as a portion of the tooth-gingiva segmentation loop 602extending along a respective one of a mesial and distal portion of theside surface of the given lower tooth 15. To that end, the processor 550can be configured to analyze the curvature of the side surface of thegiven lower tooth 15, relative to the reference plane 804, to determinethe buccal and lingual portions thereof, as described above withreference to FIGS. 9A and 9B with respect to determining the work area910. Further, the processor 550 can be configured to determine remainingportions along the side surface of the given lower tooth 15 as being themesial and distal portions, respectively.

However, in other non-limiting embodiments of the present technology,the processor can be configured to determine the given common portion1002 as being a portion of the tooth-gingiva segmentation loop 602 thatextends along a respective crown contact area between the given lowertooth 15 and one of the teeth neighboring thereto. More specifically, inthese embodiments, using the arch form 3D digital model 600, theprocessor 550 can be configured to: (1) identify areas of the givenlower tooth 15 where it touches at least one of the teeth adjacentthereto; and (2) project vertices of the tooth 3D digital model 700representative of such areas to the tooth-gingiva segmentation loop 602,thereby identifying the given common portion 1002 thereof.

Further, the processor 550 can be configured to remove the given commonportion 1002 of the tooth-gingiva segmentation loop 602 from furtherconsideration, thereby generating a refined tooth-gingiva segmentationcontour 1004, as schematically depicted in FIG. 10A, in accordance withcertain non-limiting embodiments of the present technology. Further,along a segment of the refined tooth-gingiva segmentation contour 1004corresponding to the work area 910 determined above, which in thedepicted example is a buccal segment, the processor 550 can beconfigured to determine the plurality of additional reference vertices1006.

However, in other non-limiting embodiments of the present technology,the processor 550 can be configured to identify the plurality ofadditional reference vertices 1006 among vertices of the plurality ofcontour vertices 912 of the work area 910 defined along thetooth-segmentation loop 602.

Further, it is not limited how the processor 550 can be configured todetermine a number of vertices in the plurality of additional referencevertices 1006. For example, in some non-limiting embodiments of thepresent technology, as will become apparent from the descriptionprovided below, the processor 550 can be configured to determine thenumber of vertices of the plurality of additional reference vertices1006 based on at least one of a complexity of a shape (including anumber of bends, for example) and dimensions of the base portion 306 ofthe orthodontic attachment 304 to be attached to the given lower tooth15. For example, the processor 550 can be configured to determine theplurality of additional reference vertices including 3, 4, 5, or 10vertices, for example.

However, in other non-limiting embodiments of the present technology,the processor 550 can be configured to determine the number of verticesin the plurality of additional reference vertices 1006 based on atrade-off between accuracy of defining the positioning space for theorthodontic attachment 304 and available computational resources of theprocessor 550.

Further, it is not limited how the plurality of additional referencevertices 1006 can be distributed along the work area 910; and in somenon-limiting embodiments of the present technology, the processor 550can be configured to distribute the plurality of additional referencevertices 1006 uniformly along the work area 910.

Thus, having determined, in the tooth 3D digital model 700 of the givenlower tooth 15, the reference vertex 915 and the plurality of additionalreference vertices 1006, respectively representative of the firstvertical boundary and the second vertical boundary of the positioningspace 1210 for the orthodontic attachment 304, the processor 550 can beconfigured to determine a shape of the positioning space 1210 on thesurface of the given lower tooth 15 for accommodating thereon theorthodontic attachment 304.

To that end, in some non-limiting embodiments of the present technology,the processor 550 can be configured to: (1) receive data representativeof the orthodontic attachment 304 including, for example, that of theshape and dimensions of the base portion 306 thereof, as describedabove; (2) retrieve, based on the data of the orthodontic attachment304, for example, from the solid-state drive 560 of the computingenvironment 540, data representative of a respective patterncorresponding in shape to base portion 306 of the orthodontic attachment304; and (3) fit the respective pattern on the surface of the tooth 3Ddigital model 700 between the first and second vertical boundariesdetermined.

According to certain non-limiting embodiments of the present technology,the processor can be configured to receive the data representative ofthe orthodontic attachment 304 from a dental practitioner (such as anorthodontist) involved in determining the orthodontic treatment for thesubject. However, in other non-limiting embodiments of the presenttechnology, such data can be pre-uploaded to the processor 550 as partof program instructions causing the processor 550 to execute the presentmethods.

With reference to FIG. 11 , there is depicted a schematic diagram of aplurality of patterns 1102 available for selection, by the processor550, for defining the shape of the positioning space 1210 for theorthodontic attachment 304 on the surface of the given lower tooth 15,in accordance with certain non-limiting embodiments of the presenttechnology.

For example, based on the shape of the base portion 306 of theorthodontic attachment 304, the processor 550 can be configured toselect a given pattern 1104 to further define the positioning space 1210for the orthodontic attachment 304. Further, with reference to FIGS. 12Aand 12B, there are depicted schematic diagrams of an approach tofitting, by the processor 550, the given pattern 1104 within the surfaceof the tooth 3D digital model 700, thereby defining the positioningspace 1210 for the orthodontic attachment 304 on the surface of thegiven lower tooth 15, in accordance with certain non-limitingembodiments of the present technology.

As it can be appreciated, the given pattern 1104 has (i) at least onepeak point towards the crown portion of the given lower tooth 15, thatis, a crown peak point 1202; and (ii) at least one peak towards thelower gingiva 14, that is, a first gingiva peak point 1204 and a secondgingiva peak point 1206. Thus, in accordance with certain non-limitingembodiments of the present technology, to define the positioning space1210, the processor 550 can be configured to apply at least onetransformation to the given pattern 1104 such that: (1) the crown peakpoint 1202 matches the reference vertex 915; and (2) the first gingivapeak point 1204 and the second gingiva peak point 1206 match respectiveones of the plurality of additional reference vertices 1006, such as afirst additional reference vertex 1201 and a second additional referencevertex 1203.

It is not limited how the processor 550 can be configured to determinethe first additional reference vertex 1201 and the second additionalreference vertex 1203; and in some non-limiting embodiments of thepresent technology, the processor 550 can be configured to determinethem based on the dimensions of the base portion 306 of the orthodonticappliance 304. More specifically, the processor 550 can be configured todetermine the first additional reference vertex 1201 and the secondadditional reference vertex 1203 such that the positioning space 1210 sodefined has minimal dimensions allowing accommodating therein the baseportion 306 of the orthodontic attachment 304.

In some non-limiting embodiments of the present technology, theprocessor 550 can be configured to apply one or more differenttransformations to the given pattern 1104 for fitting it within thesurface of the tooth 3D digital model 700, which can include, withoutlimitation, one or more of: translation, rotation, reflection, andscaling (e.g. stretching and/or shrinking).

However, in other non-limiting embodiments of the present technology,the processor 550 can be configured to define the positioning space 1210differently. With reference to FIGS. 13A and 13B, there are depictedschematic diagrams of another approach to fitting, by the processor 550,the given pattern 1104 within the surface of the tooth 3D digital model700 to define the positioning space 1210 for the orthodontic attachment304 on the surface of the given lower tooth 15, in accordance withcertain non-limiting embodiments of the present technology.

Broadly speaking, in these embodiments, the processor 550 can beconfigured to shape the positioning space 1210 from the plurality ofadditional reference vertices 1006. To that end, the processor 550 canbe configured to consider the plurality of additional reference vertices1006 as defining segments of a continuous curve, such that amodification to any of the so defined segments, such as stretching,translation, or rotation, would not cause the curve to break.

Thus, the processor 550 can be configured to identify, based onconsiderations of symmetry of the given pattern 1104, for example, atleast one of the plurality of additional reference vertices 1006 todisplace towards the reference vertex 915—such as a given additionalreference vertex 1305. Further, the processor 550 can be configured todisplace the given additional reference vertex 1305 along the surface ofthe tooth 3D digital model 700 towards the reference vertex 915 untilthe former matches the latter, while retaining initial positions of edgevertices, that is, in the present example, the first and secondadditional reference vertices 1201, 1203. By doing so, the processor 550can be configured to cause displacement to other ones of the pluralityof additional reference vertices 1006 scaling distances therebetweenproportionally to a displacement distance of the given additionalreference vertex 1305, as an example.

Further, in additional non-limiting embodiments of the presenttechnology, the processor 550 can be configured to join the plurality ofadditional reference vertices 1006, so re-arranged within the work area910, either with straight segments or curve segments, such as splines,as an example.

Thus, the processor 550 can be configured to define the positioningspace 1210 on the surface of the given lower tooth 15 configured foraccommodating the base portion 306 of the orthodontic attachment 304.

Determining Configuration of the Orthodontic Appliance

As noted hereinabove, in accordance with certain non-limitingembodiments of the present technology, based on data of the positioningspace 1210, the processor 550 can further be configured to update theconfiguration of the front edge 28 of the aligner 20 to enableconcurrent use thereof with the orthodontic attachment 304.

With reference to FIG. 14A, there is schematically depicted a cut line1402 for the aligner 20 determined, by the processor, in the arch form3D digital model 700, based on the data of the positioning space 1210for accommodating the orthodontic attachment 304, in accordance withcertain non-limiting embodiments of the present technology.

In some non-limiting embodiments of the present technology, theprocessor 550 can be configured to determine the cut line 1402 as aplurality of vertices 1404 following along the respective tooth-gingivasegmentation contours associated with each one of the lower teeth 12. Tothat end, for example, the processor 550 can be configured to apply oneof the approaches described in a co-owned U.S. Pat. No. 11,058,515-B1,issued on Jul. 13, 2021, and entitled “SYSTEMS AND METHODS FOR FORMINGDENTAL APPLIANCES”, the content of which is incorporated herein byreference in its entirety.

However, along the given lower tooth 15, to which the orthodonticattachment 304 is to be attached, the processor 550 can be configured todetermine the cut line 1402 as following a contour of the positioningspace 1210 determined above, thereby defining the configuration of thecut-out in the aligner 20.

Further, in some non-limiting embodiments of the present technology, theprocessor 550 can be configured to cause display of the cut line 1402within the arch form 3D digital model 600, such as on the screen 422 ofthe system 400 for presentation thereof, for example, to the dentalpractitioner involved in the development of the orthodontic treatmentfor the subject. Additionally, in some non-limiting embodiments of thepresent technology, the processor 550 can be configured to receiveinputs from the dental practitioner for modifying the cut line 1402based on their experience and expertise.

Also, in some non-limiting embodiments of the present technology, theprocessor 550 can be configured to store data indicative of the cut line1402, such as coordinates of each one of the plurality of vertices 1404thereof within the arch form 3D digital model 600, in the solid-statedrive 560 of the system 400. Further, the processor 550 can beconfigured to use the data indicative of the cut line 1402 for producingthe respective configuration of the aligner 20.

More specifically, as mentioned above, in some non-limiting embodimentsof the present technology, the processor 550 may be configured to usethe arch form 3D digital model 600 as a mold for producing theunfinished aligner using the thermoforming process. Further, theprocessor 550 can be configured to cause the marking subsystem 440 ofthe system 400 to apply each one of the plurality of vertices 1404defining the cut line 1402 onto the unfinished aligner, as mentionedabove. Further, the processor 550 may be configured to cause the formingsubsystem 450 to detect, by the camera device 452, the cut line 1402 onthe unfinished aligner and cut, by the cutting device 454, therealong,thereby producing the aligner 20 for use by the subject in the course ofthe orthodontic treatment. The aligner 20 so produced, when applied tothe lower teeth 12, would have an updated profile of the front edge 28configured for accommodating the orthodontic attachment 304 on thesurface of the given lower tooth 15.

However, in other non-limiting embodiments of the present technology,the aligner 20 can be formed from the unfinished aligner (not depicted)by manual cutting, which can be performed, for example, by an operator.To that end, in some non-limiting embodiments of the present technology,the processor 550 can be configured to emboss the cut line 1402 in abody of the arch form 3D digital model 600 such that the cut line 1402is prominent along the surface of the arch form 3D digital model 600, asschematically depicted in FIG. 14B, for example. As it can beappreciated, once the unfinished aligner has been produced using such asa configuration of the mold, the position of the cutting line 1402therealong can be determined, which may aid the operator in applying acutting tool to the unfinished aligner for forming the aligner 20. Byway of example, the cutting tool can include at least one of amechanical cutting device (such as that having a blade with a rotary orlinear cutting action, for example), a laser cutting device, or awater-jet based cutting device It should be noted that how a height ofembossment of the cutting line 1402 is selected is not limited and, insome non-limiting embodiments of the present technology, can bepredetermined, such as 2 mm, as an example. However, in othernon-limiting embodiments of the present technology, an indication of adesired height of the embossment can be received, by the processor 550,from the operator.

In yet other non-limiting embodiments of the present technology, theprocessor 550 may be configured to use the arch form 3D digital model600 with the cut line 1402 applied thereon to generate an aligner 3Ddigital model. Further, the processor 550 can be configured to causeproduction of the respective configuration of the aligner 20 by means ofthe 3D printing techniques according to the so generated aligner 3Ddigital model.

Method

Given the architecture and the examples provided hereinabove, it ispossible to execute a method for determining a position for anorthodontic attachment on a surface of the subject's tooth, such as aposition for the orthodontic attachment 304 on the surface of the givenlower tooth 15, as described above. With reference now to FIG. 15 ,there is depicted a flowchart of a method 1500, according to certainnon-limiting embodiments of the present technology. The method 1500 maybe executed by the processor 550 of the system 400.

Step 1502: Acquiring, by the Processor, a 3D Digital Model of aSubject's Arch Form, the 3D Digital Model Including a Plurality ofVertices Representing a Surface of the Given Tooth of the Subject

The method 1500 commences at step 1502 with the processor 550 beingconfigured to receive a 3D digital model of a subject's arch form, suchas the arch form 3D digital model 600 of the lower arch form 10 of thesubject, as described above with reference to FIG. 6 .

Further, as further mentioned above, in some non-limiting embodiments ofthe present technology, the processor 550 can be configured to generate,based on the arch form 3D digital model 600, the tooth 3D digital model700 of the given lower tooth 15, as an example.

The method 1500 hence advances to step 1504.

Step 1504: Determining, by the Processor, Along the Surface of the GivenTooth, a Work Area for Positioning Thereon the Orthodontic Attachment,the Work Area Having a Contour Defined by Contour Vertices of thePlurality of Vertices

At step 1504, according to certain non-limiting embodiments of thepresent technology, the processor 550 can be configured to determine,using the tooth 3D digital model 700, the work area 910 on the surfaceof the given lower tooth 15 for positioning thereon the orthodonticattachment 304.

In some non-limiting embodiments of the present technology, theprocessor 550 can be configured to determine the work area byidentifying, on the surface of the given lower tooth 15, an area ofcertain curvature—as described in greater detail above with reference toFIGS. 8, 9A, and 9B.

The method 1500 hence proceeds to step 1506.

Step 1506: Determining, by the Processor, a Reference Vertex of the WorkArea by Determining a Vertex of the Plurality of Vertices within theWork Area which is Most Distant from all of the Contour Vertices

Further, according to certain non-limiting embodiments of the presenttechnology, the processor 550 can be configured to determine, within thework area 910, the positioning space 1210 corresponding to the geometryof the base portion 306 of the orthodontic attachment 304. To that end,as described above with reference to FIG. 9B, in some non-limitingembodiments of the present technology, the processor 550 can beconfigured to determine the first and second vertical boundaries for thepositioning space 1210 within the work area 910.

According to certain non-limiting embodiments of the present technology,to determine the first vertical boundary, the processor 550 can beconfigured to determine, within the work area 910, the reference vertex915. It is not limited how the processor 550 can be configured todetermine the reference vertex 915. For example, the processor 550 canbe configured to determine the reference vertex 915 as being a center ofthe work area 910.

However, in other non-limiting embodiments of the present technology, todetermine the reference vertex 915, the processor 550 can be configuredto: (i) identify the plurality of contour vertices 912 defining thecontour of the work area 910; and (ii) determine the reference vertex915 as being a vertex of the work area 910 that is most distant from allof the plurality of contour vertices 912. In some non-limitingembodiments of the present technology, the processor 550 can beconfigured to determine such a vertex by determining a vertex of thework area 910 from which a summation of all distance values therefrom toeach one of the plurality of contour vertices 912, such as a givendistance value 916, is maximum. To that end, the processor 550 can beconfigured to apply a Dijkstra algorithm, as an example.

The method 1500 hence advances to step 1508.

Step 1508: Storing, by the Processor, Data of the Reference Vertex ofthe Work Area for Further Use in Determining the Position of theOrthodontic Attachment on the Surface of the Given Tooth

Further, at step 1508, according to certain non-limiting embodiments ofthe present technology, the processor 550 can be configured to store thedata of the reference vertex 915, such as in the solid-state drive 560,for further use in determining the positioning space 1210 for theorthodontic attachment 304.

In alternative non-limiting embodiments of the present technology, theprocessor 550 can be configured to use the reference vertex 915 fordetermining the positioning space 1210 without storing it first. Morespecifically, as mentioned above, the processor 550 can be configured todetermine the second vertical boundary within the work area 910 for thepositioning space 1210.

In some non-limiting embodiments of the present technology, theprocessor 550 can be configured to determine the second verticalboundary for the positioning space 1210 as corresponding to thetooth-gingiva segmentation loop 602 representative of the boundarybetween the given lower tooth 15 and the lower gingiva 14. Morespecifically, the processor 550 can be configured to identify, on thetooth-gingiva segmentation loop 602, the plurality of additionalreference vertices 1006, as described above with reference to FIGS. 10Aand 10B, as being representative of the second vertical boundary withinthe work area 910 for the positioning space 1210.

Further, according to certain non-limiting embodiments of the presenttechnology, the processor 550 can be configured to: (1) receive datarepresentative of the orthodontic attachment 304 including, for example,that of the shape and dimensions of the base portion 306 thereof, asdescribed above; (2) retrieve, based on the data of the orthodonticattachment 304, for example, from the solid-state drive 560 of thecomputing environment 540, data representative of a respective patterncorresponding in shape to base portion 306 of the orthodontic attachment304; and (3) fit the respective pattern on the surface of the tooth 3Ddigital model 700 between the first and second vertical boundariesdetermined.

For example, as described above with reference to FIG. 11 , in somenon-limiting embodiments of the present technology, the processor 550can be configured to select, based on the data representative of theorthodontic attachment 304, the respective pattern from the plurality ofpatterns 1102—such as the given pattern 1104.

Further, to fit the given pattern 1104 between the first verticalboundary and the second vertical boundary on the work area 910, in somenon-limiting embodiments of the present technology, the processor 550can be configured to apply one or more transformations to the givenpattern 1104, as described above with reference to FIGS. 12A and 12B.

However, in other non-limiting embodiments of the present technology, asdescribed above with reference to FIGS. 13A and 13B, the processor 550can be configured to shape the positioning space 1210 from the pluralityof additional reference vertices 1006. To that end, the processor 550can be configured to consider the plurality of additional referencevertices 1006 as defining segments of a continuous curve, such that amodification to any of the so defined segments, such as stretching,translation, or rotation, would not cause the curve to break. Further,the processor 550 can be configured to join the plurality of additionalreference vertices 1006, so re-arranged within the work area 910, asdescribed above.

Further, in accordance with certain non-limiting embodiments of thepresent technology, based on data of the positioning space 1210, theprocessor 550 can be configured to determine a cut line, such as the cutline 1402 described above with reference to FIG. 14A, defining theupdated configuration of the front edge 28 of the aligner 20.

Further, in some non-limiting embodiments of the present technology, theprocessor 550 can be configured to cause display of the cut line 1402within the arch form 3D digital model 600, such as on the screen 422 ofthe system 400 for presentation thereof, for example, to the dentalpractitioner involved in the development of the orthodontic treatmentfor the subject. Additionally, in some non-limiting embodiments of thepresent technology, the processor 550 can be configured to receiveinputs from the dental practitioner for modifying the cut line 1402based on their experience and expertise.

Also, in some non-limiting embodiments of the present technology, theprocessor 550 can be configured to store data indicative of the cut line1402, such as coordinates of each one of the plurality of vertices 1404thereof within the arch form 3D digital model 600, in the solid-statedrive 560 of the system 400. Further, the processor 550 can beconfigured to use the data indicative of the cut line 1402 for producingthe respective configuration of the aligner 20 having the updatedconfiguration of the front edge 28, as described above with reference toFIGS. 14A and 14B. This configuration of the front edge 28 of thealigner 20 can thus enable concurrent use thereof with the orthodonticattachment 304.

The method 1500 thus terminates.

Thus, certain non-limiting embodiments of the method 1500 allowdetermining the positioning space 1210 for the orthodontic attachment304 that would allow a more accurate application of the elastic forcesto the lower teeth 12 via the orthodontic elastic 302 received on theorthodontic attachment 304, as well as improved wear comfort of thealigner 20 during its concurrent use with the orthodontic attachment304.

It should be expressly understood that not all technical effectsmentioned herein need to be enjoyed in each and every embodiment of thepresent technology.

Modifications and improvements to the above-described implementations ofthe present technology may become apparent to those skilled in the art.The foregoing description is intended to providing examples ofimplementations of the present technology rather than being limiting.The scope of the present technology is therefore intended to be limitedsolely by the scope of the appended claims.

The invention claimed is:
 1. A method of determining a position of anorthodontic attachment on a surface of a given tooth of a subject, themethod being executable by a processor, the method comprising:acquiring, by the processor, a 3D digital model of a subject's archform, the 3D digital model including a plurality of verticesrepresenting a surface of the given tooth of the subject; determining,by the processor, along the surface of the given tooth, a work area forpositioning thereon the orthodontic attachment, the work area having acontour defined by contour vertices of the plurality of vertices;determining, by the processor, a reference vertex of the work area bydetermining a vertex of the plurality of vertices within the work areawhich is most distant from all of the contour vertices, the referencevertex being representative of a boundary of a space within the workarea for positioning therein the orthodontic attachment; and storing, bythe processor, data of the reference vertex of the work area for furtheruse in determining the position of the orthodontic attachment on thesurface of the given tooth.
 2. The method of claim 1, wherein: theplurality of vertices of the 3D digital model of the subject's arch formfurther includes vertices representing surfaces of a plurality of thesubject's teeth, including the given tooth, and wherein: the determiningthe contour of the work area comprises: obtaining, by the processor, ajaw curve extending through each one of the plurality of subject's teethalong the subject's arch form; determining, by the processor, areference plane extending through the given tooth, in a buccolabialdirection thereof, perpendicularly to the jaw curve; for a given vertexrepresentative of the surface of the given tooth, determining, by theprocessor, a respective angular difference between a normal vector tothe surface at the given vertex and the reference plane; in response tothe respective angular difference being greater than a predeterminedangular threshold value, removing, by the processor, the given vertexfrom further consideration; and in response to the respective angulardifference being lower than or equal to the predetermined angularthreshold value, determining, by the processor, the given vertex asbeing representative of the work area of the surface of the given toothfor positioning there on the orthodontic attachment.
 3. The method ofclaim 2, further comprising determining the jaw curve as a curveextending through respective centers of each one of the plurality of thesubject's teeth.
 4. The method of claim 1, wherein the determining thevertex of the plurality of vertices within the work area which is mostdistant from all of the contour vertices comprises determining a vertexfrom which a summation of distance values to each one of the contourvertices is maximum.
 5. The method of claim 4, wherein the determiningthe vertex from which the summation of the distance values to each oneof the contour vertices is maximum comprises applying a Dijkstraalgorithm.
 6. The method of claim 1, further comprising determining, bythe processor, the reference vertex of the work area as corresponding toa vertical boundary of the space within the work area, towards a crownof the given tooth, for positioning thereon the orthodontic attachment.7. The method of claim 6, further comprising: retrieving, from a memorycommunicatively coupled with the processor, a respective patternrepresentative of a shape of the space within the work area associatedwith the given tooth for positioning thereon the orthodontic attachment;fitting the respective pattern within the work area such that at leastone first peak point of the respective pattern positioned towards thecrown of the given tooth matches the reference vertex of the work area;and adding, by the processor, to the 3D digital model of the subject'sarch form, an indication of the respective pattern fitted within thework area associated with the given tooth for further use in producingan orthodontic appliance.
 8. The method of claim 7, wherein theplurality of vertices of the 3D digital model further includes verticesrepresenting a gingiva of the subject, and the method further comprises:obtaining, by the processor, a segmentation contour representative of aboundary between the given tooth and the gingiva; identifying, on thesegmentation contour along the work area, based on a predetermined rule,additional reference vertices for positioning the orthodonticattachment; and wherein: the fitting further comprises fitting therespective pattern within the work area such that at least one secondpeak point of the respective pattern, oppositely facing the at least onefirst peak point, matches a respective one of the additional referencevertices.
 9. The method of claim 8, wherein the additional referencevertices are distributed uniformly along the segmentation contour. 10.The method of claim 9, further comprising causing manufacture of theorthodontic appliance based at least on the determined profile of thefree end thereof.
 11. The method of claim 8, further comprisingdetermining the segmentation contour.
 12. The method of claim 11,wherein the orthodontic attachment is an elastic retaining member. 13.The method of claim 11, wherein the orthodontic appliance is anorthodontic aligner.
 14. The method of claim 8, further comprisingdetermining, based at least on a configuration of the cut-out, a profileof a free end of the orthodontic appliance configured for accommodatingtherein the orthodontic attachment.
 15. The method of claim 7, whereinthe fitting comprises scaling the respective pattern within the workarea in at least one direction thereof.
 16. The method of claim 7,wherein: the orthodontic attachment is to be applied to the given toothconcurrently with the orthodontic appliance; and a contour of the spacewithin the work area associated with the given tooth defines a cut-outin the orthodontic appliance for accommodating therein the orthodonticattachment when applied to the subject's arch form.
 17. A system fordetermining a position of an orthodontic attachment on a surface of agiven tooth of a subject, the system including: a processor and anon-transitory computer-readable memory storing instructions, and theprocessor, upon executing the instructions, being configured to: acquirea 3D digital model of a subject's arch form, the 3D digital modelincluding a plurality of vertices representing a surface, at least, ofthe given tooth of the subject; determine, along the surface of thegiven tooth, a work area for positioning thereon the orthodonticattachment, the work area having a contour defined by contour verticesof the plurality of vertices; determine a reference vertex of the workarea by determining a vertex of the plurality of vertices within thework area which is most distant from all of the contour vertices, thereference vertex being representative of a boundary of a space withinthe work area for positioning therein the orthodontic attachment; andstore data of the reference vertex of the work area for further use inpositioning the orthodontic attachment on the surface of the giventooth.
 18. The system of claim 17, wherein: the plurality of vertices ofthe 3D digital model of the subject's arch form further includesvertices representing surfaces of a plurality of a subject's teeth,including the given tooth, and wherein to determine the contour of thework area, the processor is further configured to: obtain a jaw curveextending through each one of the plurality of the subject's teeth alongthe subject's arch form; determine a reference plane extending throughthe given tooth, in a buccolabial direction thereof, perpendicularly tothe jaw curve; for a given vertex representative of the surface of thegiven tooth, determine a respective angular difference between a normalvector to the surface at the given vertex and the reference plane; inresponse to the respective angular difference being greater than apredetermined angular threshold value, remove the given vertex fromfurther consideration; and in response to the respective angulardifference being lower than or equal to the predetermined angularthreshold value, determine the given vertex as being representative ofthe work area of the surface of the given tooth for positioning there onthe orthodontic attachment.
 19. The system of claim 17, wherein todetermine the vertex of the plurality of vertices within the work areawhich is most distant from all of the contour vertices, the processor isconfigured to determine a vertex from which a summation of distancevalues to each one of the contour vertices is maximum.
 20. The system ofclaim 17, wherein the processor is further configured to: determine thereference vertex of the work area as corresponding to a verticalboundary of a space within the work area, towards a crown of the giventooth, for positioning thereon the orthodontic attachment; retrieve,from the non-transitory computer-readable memory, a respective patternrepresentative of a shape of the space within the work area associatedwith the given tooth for positioning thereon the orthodontic attachment;fir the respective pattern within the work area such that at least onefirst peak point of the respective pattern positioned towards the crownof the given tooth matches the reference vertex of the work area; andadd, to the 3D digital model of the subject's arch form, an indicationof the respective pattern fitted within the work area associated withthe given tooth for further use in producing an orthodontic appliance.